FAQ

Of course, you can use the existing switching hub, But, most non-DirectIP switching hub can’t support the specific features like DirectIP hub. 
DirectIP hub supports the following features.
- PoE functionality which is designed to be able to connect both IEEE 802.3af and IEEE 802.3at PD devices though all ports can’t connect IEEE 802.3at PD devices.
- Power on/off control for each camera
- Connection notification for each camera
Therefore, if non-DirectIP switching hubs are used in conjunction with DirectIP devices, some benefits of DirectIP will diminish.

IRE stands for Insitute of Radio Engineers and represents the composite video signal in percentage terms. That is, 100 IRE equals 100% full signal level which means 714mV amplitude active video signal.
Generally, 30 IRE is a minimum value for a detailed and acceptable image.
Most cameras represent the lux level that the maximum amplitude of the video signal is 30% or 50% of the original amplitude.

ICR

ICR (Infrared Cut Filter) is used with color CCD or CMOS image sensors to produce accurate color images. During the day, the camera uses an ICR to reflect or block mid-infrared wavelengths while passing visible lights. However, as light diminishes below a certain level, some cameras can automatically turn off ICR functionality to deliver high-quality, black and white image using infrared light.

TDN

TDN (True Day/Night) technology supports night vision capability by implementing a physical ICR that is removed by a mechanical motor.

DDN

DDN (Digital Day/Night) technology allows for viewing in both day and night conditions, without the use of an ICR. As light diminishes below a certain level, DDN technology switches color image to black and white image to offer similar benefits to TDN at a lower cost. At night, the captured image depends on the lighting and infrared waves off objects.

DOF (Depth of Field) refers to the range of distance that the subject appears acceptably sharp. DOF is determined by several factors such as aperture size, a lens to subject distance, lens focal length, and image sensor size.
Generally, the following conditions result in a deep DOF.
- small or narrow aperture size (large f-number)
- the long-distance between lens and subject
- short focal length
- small image sensor size (small image format)
A shallow DOF has a reverse condition of a deep DOF.

Surveillance cameras can be classified as indoor and outdoor models according to the installation place.

The main difference between the two models is whether the camera is weather-proof or not.

That is, the outdoor camera does completely protect the inner material from weather like wind, rain, moisture, dust, snow, and humidity.

Some outdoor cameras should have a heater or blowers for temperature resistance. On the other hand, indoor cameras do not require weather-proof or temperature resistance except critical places which get high humidity or high/low temperature.
Besides, outdoor cameras require infrared or TDN (true day/night) technology more than indoor cameras for night vision capability.